Electric boiler - Plumbers 911
14 Aug

What size hot water tank do you need? A household calculation guide

If you are in the market for a new hot water tank, make sure you purchase one big enough to handle all your family’s hot water needs. Nobody wants to end up with a head full of shampoo in a cold shower, all the hot water. 

At the same time, you don’t want to install a hot water tank that’s too big. It’s a waste of energy heating up the water you’ll never use.

This home user’s guide will walk you through choosing the perfect hot water tank for your family size and water usage.

If you need help, call Plumbers 911. You will connect to a licensed contractor who can help you figure out the right-sized tank based on your household needs.

How to calculate water use based on household size

Generally, the more people live in your house, the more water you’ll use. You can estimate using 12 gallons of water per day for each person in your home.

You can estimate that a house with four to five people will use about 50 to 60 gallons. If more than five people live in the home, you’ll need a hot water tank of about 80 gallons.

Estimating water usage habits

While calculating water needs based on household usage can give you a general estimate, every family’s water needs are different. Perhaps your home has several bathrooms, and multiple people will shower simultaneously. Maybe you’re doing several loads of laundry back to back. You might also host a larger household during holiday times. 

Here’s a rough gauge to estimate the water used for specific household tasks:

  • Sink faucet – 1 GPM
  • Shower – 2.5 GPM
  • Bathtub – 3 GPM
  • Washing machine – 3 GPM
  • Dishwasher – 3 GPM

Estimating peak hot water usage

To create an estimate that considers your family’s habits, you’ll need the maximum amount of hot water utilized. The max hot water is measured against your water heater’s first-hour rating. This first-hour rating is how much hot water your heater can produce in an hour when starting with a thoroughly heated water tank. You’ll find the first-hour rating listed in your water heater’s top left corner of the EnergyGuide label. 

Thinking about a more extensive water heater? Make sure you have room.

If you are considering upgrading to a larger water heater to accommodate more family members, check the storage area to ensure you have enough space for a bigger unit. 

If you upgrade to a bigger tank, remember that you may also need to upgrade to a bigger exhaust pipe. An improperly sized pipe can lead to carbon monoxide leaks, which can be dangerous. 

If you need to accommodate a bigger hot water tank but don’t have the space, consider upgrading to a tankless water heater. These water heaters heat water instantly without the need for a storage tank. 

Need a new water heater? Call Plumbers 911

If you need a new water heater, call Plumbers 911. You’ll connect to a licensed plumber who can recommend the right water tank for your household size and usage needs. They can also install a new water heater and recycle the old one.

All our Licensed Plumbers are specially trained, vetted and drug tested. They have undergone rigorous background checks and are fully insured and bonded. Find a local Plumbers 911 plumber in your area today!